The present invention relates, in general, to building roofs, and, more particularly, to means for attaching roof panels to building structural members.
Butler Manufacturing Company markets roofs for buildings under the trademarks MR-24 and CMR-24. These roofs include a multiplicity of panels which are seamed together and attached to the building structural elements in a manner which permits movement of those panels to accommodate thermal expansion and contraction.
There are clip units for attaching these panels to the building structural elements such as the roof purlins or the like.
Even though effective, these known clip units have several disadvantages. For example, in a unit including a tab positioned in a slot, the tab may be susceptible to frictional wear by contact with the slot edges, and might, under some circumstances, be threaded out of the slot. Furthermore, this tab might become uncentered during panel installation.
A further drawback to some known units is that the tab can "unfold" and thread out through a slot in the clip base since one end is unattached.